Now that corpses cannot be picked up, it's not possible to sacrifice a corpse sitting on an altar. Hitting 'p' always brings up the altar instead. Previously, that could be worked around by picking up the corpse, taking it off the altar, dropping it, and sacrificing it; however, that's no longer possible now, and it was always just a workaround anyway.

I'd suggest making 'p' on a square with both an altar and a corpse prompt for which one to act on.